Basics
Description
- A self-limited skin exanthem of unknown origin primarily affecting children and young adults
- Skin findings often begin with an isolated "herald patch, " an ovoid erythematous raised lesion seen along the trunk and extremities
- A secondary eruption usually follows, where multiple smaller exanthems appear along the Langer lines of the trunk and proximal extremities in a symmetric "Christmas tree pattern "
- Nearly 80% of symptoms resolve within 2 mo
Etiology
- Unknown, although there is weak evidence for a viral etiology such as herpes 6 and 7
- Many medications have been associated with a pityriasis-like reaction:
- Barbiturates
- Captopril
- Clonidine
- Gold
- Isotretinoin
- Metronidazole
- Bismuth
- Hepatitis B vaccine
- Gleevec
- Interferon
- Eczema, asthma, and underlying malignancies may be weakly associated
Diagnosis
Signs and Symptoms
Prodromal symptoms and characteristic skin findings are discussed below
History
Prodromal symptoms occur in 60 " 70% of patients:
- Malaise
- GI symptoms
- Respiratory symptoms
Physical Exam
Dermatologic findings
- Herald patch:
- Solitary, erythematous, slightly raised papule 2 " 10 cm in diameter
- Seen in 50 " 90% of cases
- Secondary eruption:
- Widespread salmon-colored, elliptic, finely scaling papules
- Usually appear symmetrically along Langer lines in a "Christmas tree " pattern
- Generally follows herald patch by 7 " 14 days
- Lesions are concentrated on the trunk and proximal extremities
- Pruritus is common
- Lesions concentrated on the face and distal extremities with minimal trunk involvement characterize inverse pityriasis
- Inverse pityriasis, lesions on the face and distal extremities characterize inverse pityriasis and may be seen more often in pediatric populations
- Rarely, pediatric presentations may have oral lesions, usually punctate hemorrhage and ulceration
Essential Workup
Exclude other diagnoses, especially when a herald patch is not seen:
- Secondary syphilis can have similar skin findings. Consider RPR in a patient with STI risk factors
- KOH prep may diagnose tinea
Diagnosis Tests & Interpretation
Lab
None required:
- KOH and RPR if other diagnoses are considered
Differential Diagnosis
- Herald patch:
- Nummular eczema
- Tinea corporis
- Secondary eruption:
- Secondary syphilis
- Drug eruption
- Guttate psoriasis
- Kaposi sarcoma
- Lichen planus
- Occult malignancy
- Scabies
- Seborrheic dermatitis
- Tinea versicolor
- Dermatomyositis
- Cutaneous lymphoma
- Lupus
Treatment
Initial Stabilization/Therapy
None required
Ed Treatment/Procedures
- Pityriasis is self-limiting
- Pruritus may improve after treatment with steroids, antihistamines, and, interestingly, erythromycin
Medication
- Diphenhydramine: Adult: 25 " 50 mg PO QID (peds: 5 mg/kg/d div. QID)
- Erythromycin: 400 mg (peds: 10 mg/kg) PO QID
- Hydrocortisone: 1% cream TID
- Prednisone: 15 " 40 mg (peds 0.25 " 0.5 mg/kg) daily
First Line
- Diphenhydramine: Adult: 25 " 50 mg PO QID (peds: 5 mg/kg/d div. QID)
- Hydrocortisone: 1% cream TID
Second Line
- Prednisone: 15 " 40 mg (peds 0.25 " 0.5 mg/kg) daily
- Erythromycin: 400 mg (peds: 10 mg/kg) PO QID
Follow-Up
Disposition
Admission Criteria
Pityriasis rosea is a self-limited disease; admission is not required
Discharge Criteria
Patients with a clear diagnosis of pityriasis rosea may be discharged
Issues for Referral
Severe refractory pruritus may require dermatology follow-up
Follow-Up Recommendations
- With primary care provider as needed
- Symptoms usually resolve over 1 " 2 mo
Pearls and Pitfalls
- Pityriasis is usually limited to the proximal extremities and trunk. Consider alternative diagnoses beyond inverse pityriasis in a patient with mucous membrane or distal extremity involvement.
- Consider alternative diagnoses in those patients who appear toxic or have atypical presentations.
Additional Reading
- Browning JC. An update on pityriasis rosea and other similar childhood exanthems. Curr Opin Pediatr. 2009;21:481 " 485.
- Chuh AA, Dofitas BL, Comisel GG, et al. Interventions for pityriasis rosea. Cochrane Database Syst Rev. 2007;(2):CD005068.
- Drago F, Broccolo F, Rebora A. Pityriasis rosea: An update with a critical appraisal of its possible herpesviral etiology. J Am Acad Dermatol. 2009;61:303 " 318.
- Stulberg DL, Wolfrey J. Pityriasis rosea. Am Fam Physician. 2004;69:87 " 91.
Codes
ICD9
696.3 Pityriasis rosea
ICD10
L42 Pityriasis rosea
SNOMED
- 77252004 Pityriasis rosea (disorder)